Electric switch



Jan. 14, 1930. o. H. PIEPER ET AL 1,743,232

- ELECTRIC SWITCH 7 Filed May 16, 1927 2 Sheets-Sheet 1 INVENTORS 65 05040-13 Pie er Jan. 14, 1930. o. H. PIEPER ET AL 1,743,232

ELECTRIC SWITCH Filed May 16, 1927 2 Sheets-Sheet 2 INVENTOR5 Oscar-E flair ATTO NE Patented Jan. 14, 1930 UNITED STATES PATENT OFFICE OSCAR H. PIEPER AND CHARLES R. MEITZLER, OF ROCHESTER, NEW YORK; SAID MEITZLER ASSIGNOR TO ALPHONSE F. PIEPER AND SAID OSCAR H, PIEPER ELECTRIC SWITCH Application filed May 16, 1927. Serial No. 191,633.

The present invention relates to electric switches and has for one object to provide an improved electric switch which can be used to control the circuits of various types of electrical apparatus and which embodies, in part, improved means adapted to prevent overrunning of the adjustable switch element when moved to and from different operating or control positions and which is adapted to positively hold the same in said positions.

A further object of the invention is to provide an improved form of switch having a novel arrangement of parts constructed and assembled in a manner to afford a compact and highly efficient switch capable of use with different forms of electric circuits and which can be manufactured at a relatively low cost.

To these and other ends the invention resides in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

In the drawings:

Figure 1 is a part sectional elevation of an electric motor showing the switch applied thereto;

Figure 2 is a rear view of the switch showing the manner of attaching the various circuit connections thereto;

Figure 3 is a front view of the switch with the cover plate removed and with the adjustable switch element in open position;

Figure 4 is a similar view showing said element in one of its closing positions;

Figure 5 is a transverse section taken on line 5 -5"- of Figure 3;

Figure 6 is a transverse section taken on line 6 -6 of Figure 3;

Figure 7 is a sectional view drawn to an enlarged scale and taken on line T -7 of Figure 3;

Figure 8 is a fragmentary view in elevation of a spring or yieldable member for holding the movable switch element in its different positions of adjustment, a portion of the latter being shown in neutral position upon the spring; and

Figure 9 is a view illustrating diagrammatically the circuit arrangement for the type of motor shown.

Similar reference characters throughout the several views indicate the same parts.

In the present embodiment of the invention we have shown, by way of example, one of a number of applications of our improved switch, the same being applied as illustrated in Figure 1 to a variable speed motor 10. In Figure 9, the switch is indicated, generally, at 11, the armature of the motor at 12, the field coil at 13 and the field resistance coil at 14 while a suitable connection block is shown at 15 and a well known form of plug at 16.

The wiring arrangement for the motor circuit is clearly illustrated in Figure 9 and will be readily understood without a detailed description of the circuit connections.

The two speed motor shown in Figure 1 may be used for driving dental lathes and various other forms of electrically driven machines where a variable speed motor is re quired. The housing of the motor is provided with an extension 17 in which is disposed the present switch comprising a casing including a switch block or base 18 constructed of insulating material, secured within the extension 17 and to the motor frame or housing by a plurality of bolts 19 which also extend through the cover plate 20 of the casing enclosing the several parts of the switch within the chamber or recess 21, separated from the recessed portion 22 by an intermediate wall portion as shown in Figures 5 and 6. In the present embodiment, two sets of contacts are shown within the chamber 21, one set being indicated by the numerals 23 and 24 and the opposite set by the numerals 25 and 26 and each being,

preferably, of the spring clip type as shown in Figure 5. The movable contact member 27 is in the form of a blade which is suitably secured to an operating handle 28 formed of insulating material and arranged to project from the lower end of the switch block through an opening therein and downwardly through an opening 29 in the extended portion 17 of the motor casing as shown in Figure 1. The handle 28 is clamped between the blade or contact plate 27 and an oppositely disposed plate 30 by means of rivets 31 as shown in Figure 7 The handle and contact 27 are pivoted upon a post 32 threaded into the block 18 and a flange 33 on the post forms a bearing for the movable contact element which is retained upon the bearing by the head of the screw 34 threaded into the post and projecting therethrough to receive one of the circuit connections which is clamped upon the bolt by a nut 35 as shown in FigureQ.

A yieldable element 36 in the form of a double acting spring having two loop-shaped yieldable portions 37 is provided for holding the movable switch element both in its open position and in its two closed positions. The spring which is preferably a leaf spring extends transversely within the recess 21 of the switch block and has its ends 38 secured upon the inner wall portions of the recess by clamplng elements 39 secured by screws 40 as indicated in Figure 6. The middle portlon oi the spring is provided wi h transversely extendlng grooves, depressions or oiiset portions 41, 42 and 43 adapted in different positions of the switch blade to receive a projection thereon preferably in the form of a roller 44 on a stud 45 carried by the blade 2'? as best indicated in Figure 7. The oiiset portions form in effect, abutments or shoulders for receiving the roller whereby the spring is made to positively hold the blade or adjustable switch element in its different positions,since, when the roller is positioned within any one of the depressions, the gripping action or frictional resistance of the spring will firmly hold said adjustable element in the desired position and upon swinging the latter from one position to another, the roller 45 will snap into the grooves so that the operator will know when the handle has been moved to the proper position. In moving the handle to swing the adjustable contact, considerable pressure is required to overcome the action of the spring in forcing the roller out of the grooves and during such operations, both of the yieldable portions 37 of the spring will serve to resist J movement of the adjustable contact, one being slightly compressed and the other tending to expand, depending on the direction in which the force is applied to the handle of the switch. It will be understood, of course,

'- that, with the switch in open position, the

roller will occupy the central groove 41 and that in its closing positions, it will occupy one or the other of the rooves 42 and 43. The central portion of the spring may be held against outward displacement by the blade 27 which does not interfere with the free movement or yieldability of the spring, the latter being secured only at its ends and thus it is permitted to expand and contract freely under action of the roller when being shifted from one groove to another.

The spring clips 23 to 26 inclusive are held in position by screws 46 extending through plates 47 in the recess 22 at the back of the switch block, the plates having binding posts 48 for the several circuit wires as shown in Figures 2 and 5. The bolt or pivot member 34 upon which the adjustable contact is adapted to swing serves as a binding post for the line wire as shown in Figure 9.

The motor shown in Figure 9 is 'of the direct current shunt type with the resistance coil 14 inserted in the field coil circuit, whereby when the switch blade is in engagement with the contacts 26 and 27 at the leftrside of the switch, the resistance will be cut in and the speed of the motor increased over that aiiorded when the resistance is cut out, as when the switch blade is in the right hand position contact and having its ends fixed upon the a base and provided with a plurality of abutments between said ends arranged to cooperate with the movable contact to positively hold it in its open and closed positions. 7

2. An electric switch comprising a base, spaced contacts thereon, a movable contact pivoted upon the base, a spring extending transversely of the movable contact and having its ends secured upon the base and provided with a plurality of depressions between said ends, and a member projecting laterally from the movable contact adapted to engage in said depressions to positively hold themovable contact in its different positions of ad- 

